Patent GB-822712-A (GB)
Title: Apparatus for automatically relatively positioning workholders, tools and the like
Inventor: SANGSTER ARLON GILBERT
IPC: G05B19/29
Filed: 1955-11-01
Abstract: 822,712. Programming for machine-tools; drilling; work-holders. SUNDSTRAND MACHINE TOOL CO. Nov. 1, 1955, No. 31224/55. Class 83 (3). Apparatus for positioning a machine-tool table or other member comprises power means 34 for moving the table 22, a control device having a series of movable control members connected to the power means, means for driving the movable control members from the table drive, and preselector means for controlling the control members, certain of the control members being movable only uni-directionally and located at the end of the series. The apparatus may move a table or tools linearly or angularly. In a drilling machine, the table 22 and slide 24 are moved by motors 34, 36 rotating screws 28, 32, beneath a drill 20 on a slide 16 movable on an arm 14 adjustable angularly on a column 12. The machine drills a number of holes automatically under the control of a tape or is operated by a number of push-buttons pressed in sequence. The drive for the slide 24 only will be described. The motor 36, Fig. 5, rotates gears 56 in one or other direction according to the setting of magnetic clutches 46, 50. The gears 56 rotate a series of shafts 58 which can be connected to drive the screw 32 at different speeds by energizing one of a series of magnetic clutches 60. At its opposite end, the screw 32 is connected to rotate a series of brushes (or move a series of brushes rectilinearly) over commutators having segments 78, 90, 92, 282, 270, Fig. 10, respectively to represent tens, ones, tenths, hundredths and thousandths of inches. Selected ones of the armature segments are energized by the tape or push-buttons so that, when a brush in a stage passes from an energized armature segment to an unenergized armature segment, or vice versa, it de-energizes a clutch 60 and energizes the clutch of the next lower stage, the brush in the tens stage being the first to operate. The clutches 46, 50 are energized according to whether a brush contacts an energized or unenergized armature first, i.e. according to whether a brush, which may be initially in any position according to the previous operation, has to travel forwards or backwards. The last two stages operate unidirectionally to eliminate backlash, there being a clutch 100 operated simultaneously with the clutch 50 to drive the last two brushes, the clutch 46 being cut-out for these stages. Tape feed.-The tape 114, Figs. 14 and 15, is drawn from the inside of a coil on pegs 120, over a reading plate 122 into a reel 128 rotated by a tape-drive motor. The tape may contain instructions for one hole, for a series of holes, or for a repeated series of holes, and may be endless. The plate 122 has a number of holes corresponding to the number of armature-segments. Each segment is connected to one of a number of contacts 144 associated with pins 142, one or more of which are allowed to pass up through the plate and the tape according to the holes in the tape. The pins may operate by causing energization or de-energization of segments. (The tape is stopped at appropriate points by a spring contact 166, Fig. 18, making contact with a terminal beneath the tape whenever a " stop " hole 146, Fig. 24, is encountered). The pins are withdrawn after an operation by depression of a plate 150 which engages enlargements 153 on the pins, the plate being raised by eccentrics 156 actuated by a rotary solenoid and lowered by springs 154. When the plate is raised and pins engage the tape, switches 164 are actuated to prevent accidental tape feed. In operation, a button is pressed to start the tape-feed motor. When a hole 146 is reached, the motor stops and is magnetically braked. The rotary solenoid is energized to raise the pins and the selected armature segments are de-energized. A tablepositioning button is then pressed, causing energization of the appropriate clutch 46 or 50 and the first-stage clutch 60. The screw 32 rotates until the first-stage brush passes from an energized to a de-energized segment, when a discharge tube fires, causing the first clutch 60 to be de-energized and the second to be energized. The other stages follow, the last two being rotated uni-directionally. Brakes.-Magnetic brakes are provided for the screw 32 and for the slide 24. Specification 766,788 is referred to.